A printer or an image forming apparatus with a printing function is a common office apparatus and gradually becomes a common home electronic apparatus. Usually, in a conventional laser printer, an image is formed on a recording medium using a detachable developing cartridge. The developing cartridge is mounted to the printer during normal operation. The developing cartridge includes a storage member, which includes a storage unit. The storage unit can be configured to store information such as the model number, the capacity, or the applied area, etc. of the developing cartridge. A main body of the printer includes contacting members which are configured to be connected to the storage member of the developing cartridge. For example, a plurality of springs may be disposed on the main body of the printer and configured to be connected to a plurality of contacts on the storage member of the developing cartridge. Therefore, the electrical connection and information communication between the printer and the storage member of the developing cartridge can be realized. In this case, the printer can obtain or rewrite the information stored in the storage member of the developing cartridge.